#define _CRT_SECURE_NO_WARNINGS
#include<stdio.h>
int main()
{
	int i = 0;
	int sum = 0;
	while (i <= 100)
	{
		if (i % 3 == 0)
		{
			sum = sum + i;
			i++;
		}
		i++;
	}
	printf("%d\n",sum);
	return 0;
}
